Definitive Technology ProSub 800: Crackling Sound after Turning OFF

[ifyoucare]

I recently laid my hands on a used ProSub 800 receiver through a reseller on OLX for a good bargain. It was all rosy initially but off late I am seeing some very weird issues come from the Subwoofer.

Since the Sub was got from this reseller who wanted to clear stock and move out of town, I could not reach back to him for the faulty product. So the issue is, the Sub is connected to a AV Receiver- Sherwood RD 6502 (same issue recreated on my main Denon AVR 1912 setup as well) LFE using an RCA connector. It works fine, booming Bass and all that. Now I am turning off the system and after like 2-5 seconds, I am hearing a crackling (or is it popping) sound from the Subwoofer that literally scared me the first time. This sound slowly reduces with intensity for a good 40 seconds or so and slowly fizzles out on its own. This happens every single time the woofer is turned OFF. Even if it is turned ON/OFF instantly. However the woofer works fine when it's ON. Also, the Pro Sub 800 has a volume kind of dial on its side and if this dial is yanked all the way to Max there is a slight hissing sound when ON. At around 75% this hissing sound is absent. But overall, it works as expected with these limitations.

Spoke to a local AV Service Center guy in bangalore who does multi-brand repairs. According to him this issue has been frequently happening with Definitive Tech brands of speakers, and he has like 5-6 speakers that are with him and are unusable. I'm not really sure I buy his story so I wanted the issue to be discussed and sorted from you guys. Are we really dealing with faulty issue speakers in a big way or is there a solution in my defense. To be frank, I love the sound from the Sub, so looking forward to your reply and hopefully a possible cracklin' solution!.

Thanks.

 

[efernand1]

Hi

Have you tried using a different Subwoofer cable?

Possibly a good servicing of the plate amplifier of the sub will help to check on circuits which are weak etc...

This popping sound is common among other subs brands too and it comes with wear n tear of use over the years

 

[sud98]

I have a Deftech Prosub for many years now. There is a loud noise if you suddenly yank off the power cable, else I havent had the other issues that you have mentioned.

 

[ifyoucare]

Hi

Have you tried using a different Subwoofer cable?

Possibly a good servicing of the plate amplifier of the sub will help to check on circuits which are weak etc...

This popping sound is common among other subs brands too and it comes with wear n tear of use over the years

Yes tried different cable, receiver and power source. Same results.

Where do you suggest I get this service done? I reside in Bangalore.

Thanks for your reply. And ya forgot to add, I ran the system today for well over 5 hours and it sounded good but after the power went off same result.

 

[sl4y3r]

I owned the ProSub800 for many years, I used to observe a pop when it was turned on but never the issue you mention. I did have an issue where it used to cause a hum when on, not off like in your case.

What I suggest you do is, use the sub, when you turn it off, quickly unplug the cables (power and LFE) and see if the sound still persists.

 

[kjong]

I owned the ProSub800 for many years, I used to observe a pop when it was turned on but never the issue you mention. I did have an issue where it used to cause a hum when on, not off like in your case.

What I suggest you do is, use the sub, when you turn it off, quickly unplug the cables (power and LFE) and see if the sound still persists.

Did u ever fix the humming sound. I have that problem now whenver plugging in the power